This invention relates to a container and more particularly to a clamshell container of the type defined by a top cover and a bottom tray, with the front and sides of the top cover extending down over the top of the upper tray periphery, and with the top cover and bottom tray being hinged together by means of a hinge line in a common rear wall.
Clamshell type cartons or packages are known, as may be seen by reference to U.S. Pat. No. 4,232,816 issued to Johnson.
Clamshell type packages are popular in the fast food industry and may be fashioned from a unitary blank of paperboard or from molded plastic. When a clamshell type container is fashioned from a unitary blank of paperboard, there often exists the tendency for the rear hinge line or fold line which joins the top cover to the bottom tray to buckle upon opening. The art is aware of constructions to inhibit or lessen the effect of such buckling, as may be seen by U.S. Pat. No. 5,221,040 issued to Sorenson as well as the Johnson patent. In spite of these attempts to prevent buckling when the top cover is opened, there still exists a need for a simple and reliable anti-buckling construction for a clamshell type carton fashioned from a unitary blank of paperboard or other stiff, foldable and resilient sheet material.